JPH0343450Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field] This invention relates to a tightening bolt,
This is an asymmetrical bolt designed to prevent it from loosening easily after tightening.

[Problems to be solved by conventional techniques and ideas]

Conventionally, there are various types of tightening bolts for preventing loosening. For example, as shown in Fig. 2A, a slit is provided vertically at the tip of the crest of the bolt 1, and the gap between the slits is reduced when the bolt is screwed in, thereby obtaining a locking effect using the repulsive force. is being attempted.
However, since the tips of the ridges are formed at acute angles, the sharp edges dig into the side walls of the ridges of the female screw during tightening, causing damage to both sides.
Plastic deformation occurred in both screw materials, causing various problems in workability and repeated use. Therefore, as shown in Fig. 2B, we improved the cross-sectional shape of the bolt 1 by making one oblique side two steps, making the entire cross-sectional shape approximately pentagonal, and starting from the top of the bolt 1. A type with a slit hanging perpendicular to the axial direction appeared. This is an attempt to solve the above problems. That is, when the bolt 1 is screwed into the slit while being reduced, the restoring force generated by this reduction generates a repulsive force that pushes back the side wall of the female screw, thereby causing the bolt 1 to tighten. Attempts are being made to prevent relaxation. However, due to the tolerance that exists between the male and female screws, gaps are created between the peaks and valleys of the bolt due to external shocks or vibrations. As a result,
When subjected to shock vibrations or lateral loads, the radial gap between the male and female threads allows for relative lateral movement. This lateral movement reduces the frictional forces between the screws. When this phenomenon occurs, the tension or load force in the male screw causes a self-relaxing rotational movement, and the bolt eventually becomes relaxed.

[Means for solving problems]

This invention was proposed in order to solve the above problem, and the angle of the hypotenuse facing the tightening direction of the bolt in the threaded part of the bolt is made to be smaller than the angle of the hypotenuse on the opposite side. This is to ensure that the moment applied to the tightened object due to external shocks or vibrations does not convert into lateral loosening motion, but instead acts as rotational motion in the tightening direction of the bolt. It is an object of the present invention to provide an asymmetrical bolt characterized by the following.

[Effect]

In the asymmetrical bolt of this invention, when the bolt is tightened, even if an external impact or vibration is generated on the threaded portion and a moment is loaded, θ ₁ > θ ₂
Therefore, even if the moment acts in the loosening direction of the bolt, there will be a large resistance in this direction, and therefore, this moment will be turned into a lateral rotational moment in the tightening direction, which has less resistance. It will be transformed.

〔Example〕

An embodiment of this invention will be described below in detail with reference to the accompanying drawings. 1 is a bolt, and the bolt 1
The angle θ ₁ of the oblique side 1a facing the direction in which the bolt 1 is tightened in the threaded portion of
It was formed to be larger than the angle θ ₂ of b. Of course, the angles θ _{1 and} θ ₂ refer to the angles between the perpendicular H to the longitudinal center line A of the bolt 1 and the respective oblique sides 1a and 1b from the top zero point of the bolt 1. In addition, 2 in the figure is
This is a nut that is tightened by this bolt 1, and as mentioned above, the angle W ₁ of the oblique side 2a facing the tightening direction is the same as that of the oblique side 2b on the opposite side.
is formed so that the angle W is greater than ₂ , but
The nut 2 itself should not be limited to this, and may be a standard product.

One embodiment of this invention has a structure not described above, so when the bolt 1 is to be tightened with the nut 2, there is a tolerance between the female and male screws as in the conventional case, and therefore, Needless to say, the tightening operation can be carried out smoothly. Therefore, once the bolt 1 is tightened, an external shock or vibration occurs, and a moment load acts on the screw.Furthermore, even if this moment load acts in the direction of loosening the bolt 1, there is a large A resistance acts and this moment is converted back into a lateral movement in the tightening direction with less resistance. That is, due to the relationship θ ₁ > θ ₂ , an external moment load always acts as a rotational moment in the direction of tightening the bolt 1, so even if the bolt 1 is subjected to an external impact or vibration, There is no relaxation at all.

[Effect of idea]

Various types of bolts that do not loosen have been proposed in the past, but in all of them, due to the tolerance between the bolt and nut, this tolerance creates gaps between the peaks and valleys of the bolt due to external shocks or vibrations, etc. A moment load was applied, and this moment load acted as a lateral movement in the loosening direction of the bolt, eventually causing the bolt to loosen, but this invention improved the tolerance between the bolt and nut. Therefore, a gap is created between the peaks and valleys of the bolt, and even if a moment is applied to this gap, this moment will be returned and act as a lateral movement in the direction of tightening the bolt of this invention, so the bolt will relax completely naturally. Then, the phenomenon described above does not occur. Therefore,
With this invention, all the various problems that existed in the past were solved.

In detail, after tightening the nut on the asymmetrical bolt of the present invention, if the bolt is deflected by an external impact force, the tightening direction should be changed as shown in Figure 1 C. Natsu 2 facing hypotenuse 1a of
There is a space P between the oblique side of the nut 2, and there is no space between the oblique side 1b on the opposite side of the oblique side 1a and the oblique side of the nut 2, which are tightly screwed together. Therefore, in a stationary state, there is a large resistance in the loosening direction of the bolt 1, and since the bolt 1 has the space P in the tightening direction, the resistance is small, so the bolt 1 is difficult to loosen. However, if the head of the bolt 1 is deflected upward due to the impact force, for example, as shown in FIG. The space P between the bolt 1 and the oblique side on the nut 2 side disappears, and the oblique side 1a on the upper side of the bolt 1 in the figure and the oblique side 1b on the lower side in the figure come into contact with the nut 2, respectively. At this time, on the upper side of the figure, the force acting in the direction of tightening the bolt 1, that is, the force acting on the oblique side 1a of the bolt 1 in the tightening direction when deflected, is due to the wedge action. According to the principle, the force acting in the direction of loosening the bolt, ie, the force acting on the opposite hypotenuse 1b, is greater.

Therefore, the impact force applied to the bolt 1 acts as a force that tightens the bolt 1 rather than as a force that loosens the bolt 1, and the bolt 1 becomes difficult to loosen.

[Brief explanation of drawings]

Figure 1A in the figure is an example of this invention.
It is a longitudinal cross-sectional side view. Figure 1B is a vertical side view of the nut, Figure 1C is a vertical side view showing the state in which the nut is screwed together, and Figures 2A and 2B are examples of the conventional type and are longitudinal cross-sectional views of the nut being disassembled. . Explanation of symbols: 1... Bolt, 1a, 1b... Hypotenuse, θ ₁ , θ ₂ ... Angle.

Claims (1)

[Scope of utility model registration request] An asymmetrical bolt characterized in that, in the threaded portion of the bolt 1, the angle θ ₁ of the oblique side 1a facing the tightening direction of the bolt is made larger than the angle θ ₂ of the oblique side 1b opposite to the oblique side 1a. .